A colleague involved in the field of emergency response made these observations at the time of the New Orleans hurricane disaster, which for their insights and sensibleness you are unlikely to see widely reported, so as a favor to YOU, I present them:
One of the largest problems is that all the disaster plans are bottom-up response mechanisms; when a city or county asks for help, the request goes to the state--when the state asks for help, the request is made to the federal government. A Federal Disaster declaration was made last Saturday (a week ago), which opened things up on the federal side to make things faster. The requests didn't come. As of yesterday, the governor of Louisiana had still not declared a state of emergency, and they didn't reach as far as their multi-state mutual aid compact until Wednesday.
EVERY federal disaster plan says that the state should be prepared to be the primary responder for 72-96 hours. By that measure, the federal response was just about on time.
There are mechanisms in place to deal with things if a government is destroyed--but in this case the mayor of New Orleans and the governor of Louisiana were still obviously present and apparently still holding the authority of their relative offices. One of the many questions that will have to be asked later is how the federal government should deal with a situation in which the local governments are not effective in dealing with the local situation AND unwilling or unable to ask for help.
In all the questions relating this to terrorist attacks, we should keep in mind that this isn't just about New Orleans; there are approximately 91,000 square miles that were dealt a catastrophic blow. The federal response has been into those areas as well and has been, in many cases, earlier and more effective because it was requested sooner and with much greater local cooperation.
You can bet that all the local and state emergency operations folks (at least in the gulf coast states) will be studying what went wrong in this response and making adjustments.
There will be a time for a careful examination of what the various elected and appointed officials did and didn't do and, perhaps, for some (many?) heads to roll. Now isn't that time. We've got what we've got, and we have too much to do for too many people to take time with that now.